It is often desired to add muzzle treatments to firearms, for example compensators, silencers, and the like to the barrel. In these situations, crush washers are commonly used to secure these muzzle treatments, which are often connected through a threaded engagement. The crush washer is placed between two parts that are threaded together and resists the threading of the components together, but deforms under pressure to give a jamming force on the mating components.
The common industry crush washer available today for firearms manufacturing consists of a conical flange or ring of material. This flange twists about itself under load, plastically deforming to provide the jamming force.
Often the common industry crush washers available provide too little crushing length (number of rotations until full crush) which does not allow for timing of components. They also often jam onto mating threads in the process of deformation making their removal difficult. These problems are caused by the challenge of small clearances. In this case of muzzle devices and barrels, the outer diameter of the crush washer must remain close to the diameter of the barrel for aesthetic reasons. Meanwhile the inner diameter of the crush washer must be larger than the major diameter of the mating threads. This only allows for a small area for the crush washer.
Thus, a need exists to have a crush washer that provides adequate crush length in situations where total maximum diameter allowable is very close to the major diameter of the shaft that crush washer is resting on.